AZATHIOPRINE for Autosomal dominant polycystic kidney disease | Polycystic liver disease

Inclusion criteria

• {"criterion_text":"- Male and female patients aged ≥18 years at the time of signing the Informed Consent Form (ICF)."}
• {"criterion_text":"- L-cohort (liver phenotype): 1. Presence of ≥20 liver cysts on imaging (MRI or CT), AND 2. Total liver volume (TLV) between 1.8 and 3.2 litres, AND 3. Presence of at least 2 out of the following 5 symptoms indicative of mass effect, regardless of intensity: o Abdominal distension perceived as uncomfortable o Frequent abdominal pain o Early satiety o Nausea (including dyspeptic complaints) o Dyspnea 4. Absence of current or prior (at least 12 weeks) treatment with Tolvaptan or somatostatin analogues"}
• {"criterion_text":"- Diagnosis of autosomal dominant polycystic kidney disease (ADPKD) based on unified criteria (i.e., combination of family history, imaging by ultrasound, MRI or CT, and/or genotyping)."}
• {"criterion_text":"- Willing and able to comply with scheduled visits, treatment plan, laboratory tests and other study procedures, as judged by the investigator."}
• {"criterion_text":"- Voluntary written informed consent of the participant or their legally authorized representative obtained prior to any screening procedures."}
• {"criterion_text":"- Use of highly effective contraception during the study period and for at least 3 months after the last dose of study treatment, for all participants of childbearing potential. This includes hormonal contraceptives, intrauterine devices, true sexual abstinence, or commitment to a vasectomized partner."}
• {"criterion_text":"- Participants with a confirmed clinical diagnosis of ADPKD. Genetic confirmation of ADPKD is not required for inclusion in the study and may be performed as part of standard clinical care during or after study participation. If a previous genetic test for ADPKD is available, it will be considered valid for the purposes of this study and does not need to be repeated, irrespective of the time since testing."}
• {"criterion_text":"- Pharmacogenetic testing for thiopurine S-methyltransferase (TPMT) deficiency is mandatory prior to initiation of study treatment with azathioprine. This testing will be performed during the 4-week screening period. Only participants with an acceptable TPMT genotype (i.e. no homozygous deficiency) will be eligible to start study medication."}
• {"criterion_text":"- Patients must be non-transplanted and not receiving immunosuppressive therapy."}
• {"criterion_text":"- K-cohort (kidney phenotype): 1. Evidence of rapidly progressive ADPKD, defined by: o Mayo Imaging Classification class 1C, 1D or 1E, and o Screening eGFR ≥ 60 mL/min/1.73 m² 2. Absence of current or prior (at least 12 weeks) treatment with Tolvaptan or somatostatin analogues 3. CT or MR documented presence of at least 3 liver cysts"}

Exclusion criteria

• {"criterion_text":"- ADPKD patients that received a kidney and/or liver transplant."}
• {"criterion_text":"- Administration of polycystic kidney disease-modifying agents (e.g. tolvaptan, Lanreotide) or interventions (such as cyst aspiration or cyst fenestration) within 12 weeks prior to the screening visit and during the screening period."}
• {"criterion_text":"- Concomitant treatment with any other immunosuppressive agent."}
• {"criterion_text":"- Women who are pregnant or breastfeeding or women of childbearing potential."}
• {"criterion_text":"- Participation in another clinical trial (other investigational drugs or devices at the time of enrolment or within 30 days prior to enrolment)."}
• {"criterion_text":"- Inability to fully understand the possible risks and benefits related to study participation."}
• {"criterion_text":"- Patients with proven TPMT deficiency"}

Primary endpoints

• {"endpoint_text":"- % of treatment stop due to leucopenia","definition_or_measurement_approach":""}
• {"endpoint_text":"- % of treatment stop due to liver function distrubances","definition_or_measurement_approach":""}
• {"endpoint_text":"- % of treatment stop due to subjective intolerance of treatment","definition_or_measurement_approach":""}
• {"endpoint_text":"- Number of infections","definition_or_measurement_approach":""}
• {"endpoint_text":"- Patient-reported outcome measures (PROs): Validated questionnaires to assess quality of life (QoL) and symptom burden (e.g. abdominal discomfort, fatigue, physical limitation) will be completed at baseline, week 8, week 32, week 56 and week 60.","definition_or_measurement_approach":"Validated questionnaires assessing QoL and symptom burden administered at baseline, week 8, week 32, week 56 and week 60."}

Secondary endpoints

• {"endpoint_text":"- Log-transformed annualised relative change of height adjusted total kidney volume (htTKV) and ht total liver volume (htTLV) (%/year) from baseline to week 56 of treatment","definition_or_measurement_approach":"Log-transformed annualised relative change calculated from baseline to week 56."}
• {"endpoint_text":"- Change in eGFR from baseline eGFR to week 52 of treatment","definition_or_measurement_approach":"Change in eGFR measured from baseline to week 52."}

Belgium

Earliest CTIS Part Ii Submission Date

10-04-2026

Latest Decision Or Authorization Date

21-04-2026

Processing Time Days

11

Number Of Sites

1

Number Of Participants

40

Primary sponsor

Full Name

UZ Leuven

Organisation Type

Hospital/Clinic/Other health care facility

Country Of Registered Address

Belgium